Electric fuse-plug.



'I'. E. MURRAY.

ELECTRIC FUSE PLUG MPL10/@10N FILED DEC. so, 1917,

1,270,048. latmod June 18, 12H8.

tion.

THOMAS E. MURRAY, or NEW YORK, N. Y.

ELECTRIC FUSE-PLUG.

Specification of Letters Patent.

Patented June 18, 1918.

Original application led December 29, 1916, Serial No. 139,503. Divided and this application led December 10, 1917. Serial No. 206,401.

To all whom t may concern.

Be it known that I, THOMAS E. MURRAY, a citizen of the United States, residing at-New York, in the county of New York and State of `N ew York, have invented a certain new and useful Improvement in Electric Fuse- Ilugs, of which the following is a specifica- The invention is an electric fuse plug, and consists in the construction more particularly hereinafter set forth.

This application is a division of my pending application Serial No. 139,508, filed December 29, 1916.

In the accompanying drawings- Figure l is a section 0f my fuse plug seated in a mold, in which it is preferably torna-fl. Fig. 2 is a side View of the metal cap.

Similar letters of reference indicate like parts.

A is a shell of metal, here shown seated in a recess in the forming block B. Said shell is internally threaded to receive a lining shell C. D is a button contact having an upward projection IC. l" .is the fuse strip connected at its ends respectively to the projec tion E and the shell C.

After the aforesaid parts are placed in the molding block B, VI pour into the shell plaster of' Paris to form a bottom layer (l. Aftcr'said plaster'oflaris has hardened, I insert a llayer H of comminuted refractory material, such as dry laster. Layer H incloses the blowing point of the fuse strip, indicated at I.

' J, Fig. 2, isa cap or cover having a central opening K, and a flange L around said opening. Said flange is indented at its edge,

and the teeth thus formed are spread out' opening in said cap,

wardly. When the cap is in position, as shown in Fig. l, the lower ends of the flange enter layer H of comminuted material. Afterward another layer M Aof insulating, material is poured into the shell through the thus embedding the flange L and holding the cap firmly in position.

I claim:

1. A fusevplug of the' type wherein the contacts are respectively a threaded shell and aplate at one end of said plug, and a fuse strip connecting said contacts, a mass of insulating material within said shell, comprising a layer of dense solid material and a layer of dry' comminuted material, a cover cap for said shell having a -central opening, and a flange around said opening, the body portieri of said flange being embedded in said layer of dense solid material, and the end of 'said flange entering said layer of dry comminuted material.

2. A fuse plug of the type set forth in claim l, having a blowingr point localized in said layer of dry comminuted material and within the areas circumscribed by said flange.

3. A fuse plug of the type set forth in claim 1, there being a plurality of layers of dense. solid insulating material and an intervening layer of dry comminuted material, the said fuse strip having its terminals. connected to said contacts within the said layers of dense solid material.

In testimony whereof I have affixed my signature in presence of two witnesses.-

'THOMAS E. MURRAY. VVitn'esses GEm'RUDE T. PORTER, MAY T. MCGARRY. 

